1. Field of the Invention
This invention relates to a camera system arranged to permit use of not only interchangeable lenses of the conventional camera system but also interchangeable lenses having a shorter back focal distance than the conventional camera system.
2. Description of Related Art
It has been known to use a mount adapter in mounting a detachable interchangeable lens on a camera body not designed for use of that lens, as disclosed in Japanese Laid-Open Patent Application No. HEI 2-35428.
Meanwhile, in Japanese Laid-Open Utility Model Application No. HEI 5-25435, there is disclosed a technique of setting an interchangeable lens to which a mount adapter is attachable and an interchangeable lens to which the mount adapter is not attachable, by suitably configuring a bayonet mount of the mount adapter and bayonet mounts of the interchangeable lenses.
More specifically, a protruding part is formed at a part of the mount adapter where no bayonet claw is formed. The bayonet mount of the interchangeable lens to which the mount adapter is attachable is in a shape obtained by cutting off its part interfering with the protruding part. The bayonet mount of the interchangeable lens to which the mount adapter is not attachable, on the other hand, is in a shape having its part interfering with the protruding part not cut off. Accordingly, even if the mount adapter is intended to be attached to the interchangeable lens to which the mount adapter is not attachable, the mount adapter cannot be attached to that interchangeable lens, because the protruding part of the mount adapter interferes with that part of the bayonet mount of that interchangeable lens.